Organic light emitting diode (OLED) display technology attracts more and more attention. However, many organic materials are sensitive to moisture and oxygen and cannot endure a high temperature; in addition, oxidation of metal electrodes can also degrade performances of an organic light-emitting diode. Thus it is important to isolate the organic light-emitting diode from oxygen and water in order to prolong a lifetime of the organic light-emitting diode.